where to start?

I've known the basic rules of chess for a long time, but I'm not sure how to start building the foundation of good chess playing. Should I be playing as many actual games as possible, or should i be studying a specific opening? Without much experience, how can i play without murdering my rating to begin with, or how could i know what opening i want to study? Thus far, I've mostly been doing tactics training and the virtual chess mentor. I have a lot of time on my hands at the moment, and believe if I knew what specific activity or activities I should be focusing on, it would help improve my game a lot faster than it's current pace.

Any book or online reference you would like to suggest would also be greatly appreciated.

1) Forget about your rating for now. A high rating does not make your chess play better. It's the other way around... playing better will improve your rating. Concentrate on improving your game, and afterwards your rating will quickly recover from whatever damage it takes during the learning period.

2) Forget about studying a specific opening until you are happy with your overall playing strength. A good grasp of general opening principles (center control, development, economy of weakness, tempo) will do far more to improve your play than any memorization of specific lines could.

3) Study tactics. Tactics, tactics, tactics. First the basic tactical elements: pins, forks, skewers, overload, decoying, deflection, guard destruction, and so on... then work on combining those basic elements into sequences; that's why they are called "combinations". Study model mates: corridor mates, smothered mates, Lolli, Greco, Philidor's, Morphy's, Paulsen's, Legal's, Anastasia's, Anderssen's mates.

4) Study simple endgames. Start with the easy ones: mates with King and Pieces (King and Queen, King and Rook, King and two Bishops). Then proceed to King and Pawn endings, King plus Rook and Pawn endings, King plus minor piece and Pawn endings. Examine a few instructive studies (those are composed endgames, arranged to illustrate a particular point).

5) Learn to read the Pawn formation. In more than half of typical positions, the Pawn formation is trying to tell you what your plan should be, but many players don't know how to read it. Learn about Rams, Duos, Levers, Chains, Twins. Read "Pawn Power in Chess" by Kmoch, or "Pawn Structure Chess" by Soltis.

6) Play. Play, play, play. Not blitz... you want to play at slow time controls, so that you can actually THINK over your moves. You will find it much easier to assimilate and organize the material that you're learning if you play regularly and try out the new ideas against a live opponent.

7) Record your games. Analyze them afterwards, especially the losses. It's painful, but it's a reliable road to self-improvement. If you aren't certain that you KNOW why you lost a particular game, post it on the forum and ask for advice.

8) When you are satisfied with the progress that you're making, THEN start picking a few openings that you feel will suit your playing style, and study them.

"Should I be playing as many actual games as possible?"

Yes.  Some old recommendation (I think is was Capablanca) says the newer you are the more "study" time should be spent playing games.

"or should i be studying a specific opening?"

My advice is after a game ends, use the opening explorer here (or at chessgames.com) to see who left book first.  If you were uncomfortable in the opening play over a few GM games that contained that opening, the whole game from start to finish (free source of games at chessgames.com, use ECO option to narrow search to specific openings).  Over time this builds your opening repertoire the right way... exposing you to common middlegame maneuvers.  Memorizing openings is close to completely useless.  Should be referencing them with the middlegames (e.g. oh, in the french defense I see black expanding on the queenside a lot, that must be a good plan).

"Without much experience, how can i play without murdering my rating to begin with?"

It's unfortunate for players who want to improve and are rated under... lets say 2000 that they even get a rating.  Ratings help you track progress over long period of time.  What should be at the forefront of an improving player's mind is what they can learn from their last game (not whether they won or lost it).  To take an example from the openings, maybe you crushed your opponent after 40 moves, but you know, in the opening or at some point later in the game you felt unsure.  So after a little celebration (yay, I won!) go back and try to resolve that uncertainty.  Club players in your area / the chess.com analysis forum can help with that.  Share your thoughts and ask for advice.

"how could i know what opening i want to study?"

IMO (and many others) start by placing a center pawn (king's or queen's pawn) two squares forward.  The ideas and maneuvers are not only more accessible but also give new players a chance to put into practice some of the most fundamental ideas (tempos are important, development, owning central space).  So for white openings like the Italian, Ruy, and queen's gambit declined.  The Ruy and QGD are often seen in world class tournaments too, so the experience you gain in these openings can easily serve you a lifetime.  On the Black side openings like the Ruy, philidor's, QGD, and Slav.  Oh, and don't study them specifically.  Just start playing them and reviewing games like I mentioned earlier.  As far as opening study simply learn the principals (basically: utility of development, the center, castling).

"I've mostly been doing tactics training . . ."

Just a brief comment to tactics training.  If there were only one, this would be the most important exercise for amateur players.  Not only are the majority of games won and lost due to tactics (so these patterns are very useful to know) but by solving them you're also practicing visualization / calculation skills.

"if I knew what specific activity or activities I should be focusing on . . ."

Play lots of games where you have all the time you need to think through your moves.  If 30 minute games are too fast you can start with "online chess" (their correspondence chess) where you have days to move.

For study tactics training is great.  Play over GM games now and then when you're unsure about an opening, and post in the analysis section.  You can also get a book / membership here gives access to many articles and videos.

"Any book or online references?"

Any book of the the 5 in Seriwan's Winning Chess Series (e.g. openings, endgames, tactics, strategy).

Logical Chess Move by Move -- by Chernev (A collection of games where the author gives comments for every move in every game).

Understanding Chess Move by Move -- by Nunn (Same kind as above).

The Complete Chess Player -- by Reinfeld is a good first book, containing a bit of info on everything.

Well known trainer Dan Heisman has written many articles over the years.  Here's a link with a lot of free instructional material: http://danheisman.home.comcast.net/~danheisman/Main_Chess/ChessDotCom.htm

Wow. Everyone gave so much information, very much appreciated :)

http://www.chess.com/blog/NimzoRoy/endgame-faqs?_domain=old_blog_host&_parent=old_frontend_blog_view

http://www.chess.com/blog/NimzoRoy/chess-opening-principles?_domain=old_blog_host&_parent=old_frontend_blog_view

http://www.chess.com/blog/NimzoRoy/beginner-chess-book-recommendations